I like it.
Reviewed-by: Jason Ekstrand <ja...@jlekstrand.net>
It might be worth adding a comment somewhere (maybe right above the middle
loop) that describes the access patterns we talked about yesterday. In
particular, that we're covering a whole cache line at a time in the tiled
image and should be getting maximum caching from the linear image as well
assuming at least 4 lines can fit in cache at a time. Bonus points for an
ASCII art picture. :)
On Fri, Jan 26, 2018 at 4:07 PM, Scott D Phillips <
scott.d.phill...@intel.com> wrote:
> TileY's low 6 address bits are: v1 v0 u3 u2 u1 u0
> Thus a cache line in the tiled surface is composed of a 2d area of
> 16x4 bytes of the linear surface.
>
> Add a special case where the area being copied is 4-line aligned
> and a multiple of 4-lines so that entire cache lines will be
> written at a time.
>
> On Apollolake, this increases tiling throughput to wc maps by
> 84.0103% +/- 0.862818%
>
> v2: Split [y0, y1) and [y2, y3) loops apart for clarity (Jason Ekstrand)
> v3: Don't reset src var (Jason), Ensure y0 <= y1 <= y2 <= y3
> ---
> src/mesa/drivers/dri/i965/intel_tiled_memcpy.c | 72
> +++++++++++++++++++++++---
> 1 file changed, 66 insertions(+), 6 deletions(-)
>
> diff --git a/src/mesa/drivers/dri/i965/intel_tiled_memcpy.c
> b/src/mesa/drivers/dri/i965/intel_tiled_memcpy.c
> index 53a5679691..a362891d7e 100644
> --- a/src/mesa/drivers/dri/i965/intel_tiled_memcpy.c
> +++ b/src/mesa/drivers/dri/i965/intel_tiled_memcpy.c
> @@ -287,7 +287,7 @@ linear_to_xtiled(uint32_t x0, uint32_t x1, uint32_t
> x2, uint32_t x3,
> */
> static inline void
> linear_to_ytiled(uint32_t x0, uint32_t x1, uint32_t x2, uint32_t x3,
> - uint32_t y0, uint32_t y1,
> + uint32_t y0, uint32_t y3,
> char *dst, const char *src,
> int32_t src_pitch,
> uint32_t swizzle_bit,
> @@ -306,6 +306,9 @@ linear_to_ytiled(uint32_t x0, uint32_t x1, uint32_t
> x2, uint32_t x3,
> const uint32_t column_width = ytile_span;
> const uint32_t bytes_per_column = column_width * ytile_height;
>
> + uint32_t y1 = MIN2(y3, ALIGN_UP(y0, 4));
> + uint32_t y2 = MAX2(y1, ALIGN_DOWN(y3, 4));
> +
> uint32_t xo0 = (x0 % ytile_span) + (x0 / ytile_span) *
> bytes_per_column;
> uint32_t xo1 = (x1 % ytile_span) + (x1 / ytile_span) *
> bytes_per_column;
>
> @@ -321,24 +324,81 @@ linear_to_ytiled(uint32_t x0, uint32_t x1, uint32_t
> x2, uint32_t x3,
>
> src += (ptrdiff_t)y0 * src_pitch;
>
> - for (yo = y0 * column_width; yo < y1 * column_width; yo +=
> column_width) {
> + if (y0 != y1) {
> + for (yo = y0 * column_width; yo < y1 * column_width; yo +=
> column_width) {
> + uint32_t xo = xo1;
> + uint32_t swizzle = swizzle1;
> +
> + mem_copy(dst + ((xo0 + yo) ^ swizzle0), src + x0, x1 - x0);
> +
> + /* Step by spans/columns. As it happens, the swizzle bit flips
> + * at each step so we don't need to calculate it explicitly.
> + */
> + for (x = x1; x < x2; x += ytile_span) {
> + mem_copy_align16(dst + ((xo + yo) ^ swizzle), src + x,
> ytile_span);
> + xo += bytes_per_column;
> + swizzle ^= swizzle_bit;
> + }
> +
> + mem_copy_align16(dst + ((xo + yo) ^ swizzle), src + x2, x3 - x2);
> +
> + src += src_pitch;
> + }
> + }
> +
> + for (yo = y1 * column_width; yo < y2 * column_width; yo += 4 *
> column_width) {
> uint32_t xo = xo1;
> uint32_t swizzle = swizzle1;
>
> - mem_copy(dst + ((xo0 + yo) ^ swizzle0), src + x0, x1 - x0);
> + if (x0 != x1) {
> + mem_copy(dst + ((xo0 + yo + 0 * column_width) ^ swizzle0), src +
> x0 + 0 * src_pitch, x1 - x0);
> + mem_copy(dst + ((xo0 + yo + 1 * column_width) ^ swizzle0), src +
> x0 + 1 * src_pitch, x1 - x0);
> + mem_copy(dst + ((xo0 + yo + 2 * column_width) ^ swizzle0), src +
> x0 + 2 * src_pitch, x1 - x0);
> + mem_copy(dst + ((xo0 + yo + 3 * column_width) ^ swizzle0), src +
> x0 + 3 * src_pitch, x1 - x0);
> + }
>
> /* Step by spans/columns. As it happens, the swizzle bit flips
> * at each step so we don't need to calculate it explicitly.
> */
> for (x = x1; x < x2; x += ytile_span) {
> - mem_copy_align16(dst + ((xo + yo) ^ swizzle), src + x,
> ytile_span);
> + mem_copy_align16(dst + ((xo + yo + 0 * column_width) ^ swizzle),
> src + x + 0 * src_pitch, ytile_span);
> + mem_copy_align16(dst + ((xo + yo + 1 * column_width) ^ swizzle),
> src + x + 1 * src_pitch, ytile_span);
> + mem_copy_align16(dst + ((xo + yo + 2 * column_width) ^ swizzle),
> src + x + 2 * src_pitch, ytile_span);
> + mem_copy_align16(dst + ((xo + yo + 3 * column_width) ^ swizzle),
> src + x + 3 * src_pitch, ytile_span);
> xo += bytes_per_column;
> swizzle ^= swizzle_bit;
> }
>
> - mem_copy_align16(dst + ((xo + yo) ^ swizzle), src + x2, x3 - x2);
> + if (x2 != x3) {
> + mem_copy_align16(dst + ((xo + yo + 0 * column_width) ^ swizzle),
> src + x2 + 0 * src_pitch, x3 - x2);
> + mem_copy_align16(dst + ((xo + yo + 1 * column_width) ^ swizzle),
> src + x2 + 1 * src_pitch, x3 - x2);
> + mem_copy_align16(dst + ((xo + yo + 2 * column_width) ^ swizzle),
> src + x2 + 2 * src_pitch, x3 - x2);
> + mem_copy_align16(dst + ((xo + yo + 3 * column_width) ^ swizzle),
> src + x2 + 3 * src_pitch, x3 - x2);
> + }
>
> - src += src_pitch;
> + src += 4 * src_pitch;
> + }
> +
> + if (y2 != y3) {
> + for (yo = y2 * column_width; yo < y3 * column_width; yo +=
> column_width) {
> + uint32_t xo = xo1;
> + uint32_t swizzle = swizzle1;
> +
> + mem_copy(dst + ((xo0 + yo) ^ swizzle0), src + x0, x1 - x0);
> +
> + /* Step by spans/columns. As it happens, the swizzle bit flips
> + * at each step so we don't need to calculate it explicitly.
> + */
> + for (x = x1; x < x2; x += ytile_span) {
> + mem_copy_align16(dst + ((xo + yo) ^ swizzle), src + x,
> ytile_span);
> + xo += bytes_per_column;
> + swizzle ^= swizzle_bit;
> + }
> +
> + mem_copy_align16(dst + ((xo + yo) ^ swizzle), src + x2, x3 - x2);
> +
> + src += src_pitch;
> + }
> }
> }
>
> --
> 2.14.3
>
>
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